Some resorts have additional land or plans for more construction that hasn't been started due to the downturn in the economy.
An example would be a resort I own, Marriott's Grand Chateau in Las Vegas. At one point sales were so brisk they had planned on combining the construction of the final two towers (to be built concurently vs consecutively) to save on construcion cost and speed up the completion date. Under those plans the resort would have been just about completed by now.
As it is, the economy collapsed and all constrcution was halted. Now they're finally starting on the third tower. If a you didn't know there were plans for two more towers, the resort actually looks built out as it stands now.
HGVC on the LV Strip is the same way. As it stands it appears completed but, the reality is they have planse for two more towers.
French Quarter Resort in Branson and Marriott's Willow Ridge Resort in Branson have additional plans for more buildings but, construction on both of those projects has currently been halted. Marriott has a handful of resorts that I'm aware of where construction has been halted due to slower sales.
Chances are there are plans for additional construction which has been halted but, those plans may still be active. It's probably best for I.I. to continue to list the possibility of construction rather than take the warning away. If you booked a resort now and there was no warning, then by the time you're vacation rolled around, maybe they've restarted construction and you're not a happy exchanger because I.I. "should have known" and warned you.
Either way, I.I., or even RCI, won't win. People will be wondering what they're talking about when there's no active construction or, they'll be mad if they arrive at the resort and their vacation is ruined by all the noise of construction.